xnet/pipenet: TODO to fixit for TCP semantic

On TCP port(accepted) = port(listen), i.e.  When we connect
www.nexedi.com:80, remote addr of socket will have port 80.  Likewise on
server side accepted socket will have local port 80.  The connection
should be thus fully identified by src-dst address pair.

However currently pipenet, when accepting connection, allocates another
free port at acceptor side.

xnet/pipenet/pipenet.go

@@ -30,14 +30,19 @@
 //
 //	l, err := h1.Listen(":10")          // starts listening on address "abc:10"
 //	go func() {
-//		csrv, err := l.Accept()  // csrv will have LocalAddr "abc:10"
+//		csrv, err := l.Accept()     // csrv will have LocalAddr "abc:1"
 //	}()
-//	ccli, err := h2.Dial("abc:10")   // ccli will have RemoteAddr "def:10"
+//	ccli, err := h2.Dial(ctx, "abc:10") // ccli will be connection between "def:1" - "abc:1"
 //
 // Pipenet might be handy for testing interaction of networked applications in 1
 // process without going to OS networking stack.
 package pipenet
 
+// TODO Fix pipenet for TCP semantic: there port(accepted) = port(listen), i.e.
+//     When we connect www.nexedi.com:80, remote addr of socket will have port 80.
+//     Likewise on server side accepted socket will have local port 80.
+//     The connection should be thus fully identified by src-dst address pair.
+
 import (
 	"context"
 	"errors"